I. Field of the Invention
The present invention relates generally to the fields of molecular biology, immunology and neurobiology. More particularly, it concerns the identification of peptoids that are recognized by neurodegenerative disease (ND)-specific antibodies. These peptoids can be used to identify subjects suffering from or at risk of NDs.
II. Description of Related Art
Alzheimer's Disease (AD) is a progressive and fatal brain disease that affects as many as 5.3 million Americans. AD destroys brain cells, causing problems with memory, thinking and behavior. These symptoms get worse over time, and ultimately the disease is fatal. Today, it is the sixth-leading cause of death in the United States and is the most common form of dementia, accounting for 50-70% of all dementia cases. Sadly, while treatments for symptoms exist, there is no cure.
Diagnosing Alzheimer's Disease is an empirical process that involves several types of evaluations and may take many days to weeks to complete. Evaluations include taking a detailed medical history and physical examination. In addition, standard laboratory tests including blood, urine and CSF tests are mainly designed to help eliminate other possible conditions. Neuropsychological testing, using a variety of tools to assess memory, problem-solving, attention, vision-motor coordination and abstract thinking, are also performed. Tests for depression should also be included. Finally, brain-imaging scans are recommended to rule out brain tumors or blood clots in the brain as the reason for symptoms. In sum, there is currently no single test that accurately diagnoses Alzheimer's Disease, with a definitive diagnosis of Alzheimer's possible only by examining brain tissue after death.
Parkinson's Disease (PD) is another degenerative disease of the brain (central nervous system) that often impairs motor skills, speech, and other functions. It affects movement (motor symptoms), but other typical symptoms include disorders of mood, behavior, thinking, and sensation (non-motor symptoms). Patient's individual symptoms may be quite dissimilar and progression of the disease is also distinctly individual. The symptoms of PD result from the loss (idiopathic or genetic, toxic or traumatic) of pigmented dopamine-secreting (dopaminergic) cells in the pars compacta region of the substantia nigra (literally “black substance”). These neurons project to the striatum and their loss leads to alterations in the activity of the neural circuits within the basal ganglia that regulate movement, in essence an inhibition of the direct pathway and excitation of the indirect pathway.
Diagnosis of PD presents similar if somewhat distinct challenges. When performing a neurologic examination to evaluate a patient with any movement disorder, the doctor should take a medical history and perform a physical examination. In addition, a neurologic exam is conducted to make a thorough evaluation of the nervous system, including observing aspects of the patient's movement, coordination and balance. Laboratory testing of the blood of patients with the symptoms typical of Parkinson's only rarely uncovers any abnormality. Electroencephalograms (EEG's) record some aspects of brain electrical activity, but they are not effective in spotting PD. The MRI and CAT scans of the brain produce remarkable and exquisite anatomic pictures, but the brains of people with PD disease appear normal even under this scrutiny because the changes associated with PD are microscopic and are not revealed by these scans. With no definitive diagnostic tests to provide specific answers, physicians must base their diagnosis of PD on judgment.
Thus, there remains a need for diagnostic procedures for both of these diseases and other neurological diseases that are (i) accurate and objective, (ii) simple and reproducible, and (iii) useful in both early and late stage case.